cannabinoids

Drugs of Abuse

• Amphetamines
• Opiates
• Ethanol (Alcohol)
• Cocaine
• Cannabinoids
• Phencyclidine

Common use

Specimen

Workplace drug-screening programs, because of the potential medicolegal consequences associated with them, require collection of urine and blood specimens using a chain of custody protocol. The protocol provides securing the sample in a sealed transport device in the presence of the donor and a representative of the donor’s employer, such that tampering would be obvious. The protocol also provides a written document of specimen transfer from donor to specimen collection personnel, to storage, to analyst, and to disposal.

Normal findings

Description

This procedure is contraindicated for

N/A

Indications

• Differentiate alcohol intoxication from diabetic coma, cerebral trauma, or drug overdose
• Investigate suspected drug abuse
• Investigate suspected drug overdose
• Investigate suspected noncompliance with drug or alcohol treatment program
• Monitor ethanol levels when administered to treat methanol intoxication
• Routine workplace screening

	Screening Cutoff Concentrations for Drugs of Abuse Recom-mended by SAMHSA	Confirmatory Cutoff Concentrations for Drugs of Abuse Recommended by SAMHSA	Detectable Duration After Last Single-Use Dose	Detectable Duration After Last Dose: Prolonged Use
Hallucinogens
Cannabinoids	50 ng/mL	15 ng/mL	2–7 days	1–2 mo
Phencyclidine	25 ng/mL	25 ng/mL	1 wk	2–4 wk
Opiates	2,000 ng/mL	2,000 ng/mL	1–3 days	1–3 days
6–Acetylmorphine	10 ng/mL	10 ng/mL	20 hr	1–7 days
Stimulants
Amphetamines (either amphetamine or methamphetamine)a	500 ng/mL	250 ng/mL	48 hr	7–10 days
Cocaine	150 ng/mL	100 ng/mL	3 days	4 days
MDMA (either methylenedioxymethamphetamine, methylenedioxyamphetamine, or methylenedioxyethylamphetamine)	500 ng/mL	250 ng/mL	24 hr	24 hr

^a To be reported as positive for methamphetamine, the specimen must also contain amphetamine at a concentration of 100 ng/mL or greater.

Potential diagnosis

A urine screen merely identifies the presence of these substances in urine; it does not indicate time of exposure, amount used, quality of the source used, or level of impairment. Positive screens should be considered presumptive. Drug-specific confirmatory methods should be used to investigate questionable results of a positive urine screen.

Critical findings

• Note and immediately report to the health-care provider (HCP) any critically increased values and related symptoms.

• It is essential that a critical finding be communicated immediately to the requesting health-care provider (HCP). A listing of these findings varies among facilities.

• Timely notification of a critical finding for lab or diagnostic studies is a role expectation of the professional nurse. Notification processes will vary among facilities. Upon receipt of the critical value the information should be read back to the caller to verify accuracy. Most policies require immediate notification of the primary HCP, Hospitalist, or on-call HCP. Reported information includes the patient’s name, unique identifiers, critical value, name of the person giving the report, and name of the person receiving the report. Documentation of notification should be made in the medical record with the name of the HCP notified, time and date of notification, and any orders received. Any delay in a timely report of a critical finding may require completion of a notification form with review by Risk Management.

• The legal limit for ethanol intoxication varies by state, but in most states, greater than 80 mg/dL (0.08 %) is considered impaired for driving. Levels greater than 300 mg/dL are associated with amnesia, vomiting, double vision, and hypothermia. Levels of 80 to 400 mg/dL are associated with coma and may be fatal. Possible interventions for ethanol toxicity include administration of tap water or 3% sodium bicarbonate lavage, breathing support, and hemodialysis (usually indicated only if levels exceed 300 mg/dL).

• Amphetamine intoxication (greater than 200 ng/mL) causes psychoses, tremors, convulsions, insomnia, tachycardia, dysrhythmias, impotence, cerebrovascular accident, and respiratory failure. Possible interventions include emesis (if orally ingested and if the patient has a gag reflex and normal central nervous system [CNS] function), administration of activated charcoal followed by magnesium citrate cathartic, acidification of the urine to promote excretion, and administration of liquids to promote urinary output.

• Cocaine intoxication (greater than 1,000 ng/mL) causes short-term symptoms of CNS stimulation, hypertension, tachypnea, mydriasis, and tachycardia. Possible interventions include emesis (if orally ingested and if the patient has a gag reflex and normal CNS function), gastric lavage (if orally ingested), whole-bowel irrigation (if packs of the drug were ingested), airway protection, cardiac support, and administration of diazepam or phenobarbital for convulsions. The use of beta blockers is contraindicated.

• Heroin and morphine are opiates that at toxic levels (greater than 200 ng/mL) cause bradycardia, flushing, itching, hypotension, hypothermia, and respiratory depression. Possible interventions include airway protection and the administration of naloxone (Narcan).

• PCP intoxication (greater than 100 ng/mL) causes a variety of symptoms depending on the stage of intoxication. Stage I includes psychiatric signs, muscle spasms, fever, tachycardia, flushing, small pupils, salivation, nausea, and vomiting. Stage II includes stupor, convulsions, hallucinations, increased heart rate, and increased blood pressure. Stage III includes further increases of heart rate and blood pressure that may culminate in cardiac and respiratory failure. Possible interventions may include providing respiratory support, administration of activated charcoal with a cathartic such as sorbitol, gastric lavage and suction, administration of IV nutrition and electrolytes, and acidification of the urine to promote PCP excretion.

Interfering factors

• Codeine-containing cough medicines and antidiarrheal preparations, as well as ingestion of large amounts of poppy seeds, may produce a false-positive opiate result.
• Adulterants such as bleach or other strong oxidizers can produce erroneous urine drug screen results.
• Alcohol is a volatile substance, and specimens should be stored in a tightly stoppered containers to avoid falsely decreased values.

Nursing Implications and Procedure

Pretest

• Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
• Patient Teaching: Inform the patient this test can assist with identification of drugs in the body.
• Obtain a history of the patient’s complaints, including a list of known allergens, especially allergies or sensitivities to latex.
• Obtain a history of the patient’s symptoms and previously performed laboratory tests and diagnostic and surgical procedures.
• Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values online at DavisPlus).
• Review the entire procedure with the patient, especially if the circumstances require collection of urine and blood specimens using a chain-of-custody protocol. Inform the patient that specimen collection takes approximately 5 to 10 min but may vary depending on the level of patient cooperation. Address concerns about pain and explain that there may be some discomfort during the venipuncture, but there should be no discomfort during urine specimen collection.
• Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
• Note that there are no food, fluid, or medication restrictions unless by medical direction.
• If appropriate or required: Make sure a written and informed consent has been signed prior to the procedure.

Intratest

• Potential complications: N/A
• Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
• Instruct the patient to cooperate fully and to follow directions. Direct the patient receiving venipuncture to breathe normally and to avoid unnecessary movement.
• Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient, and label the appropriate collection containers with the corresponding patient demographics, initials of the person collecting the specimen, date, and time of collection. For alcohol level, use an approved non–alcohol-containing solution to cleanse the venipuncture site before specimen collection. Perform a venipuncture, as appropriate. For a urine drug screen, instruct the patient to obtain a clean-catch urine specimen.
• Remove the needle and apply direct pressure with dry gauze to stop bleeding. Observe/assess venipuncture site for bleeding or hematoma formation and secure gauze with adhesive bandage.

Clean-Catch Specimen

• Instruct the male patient to (1) thoroughly wash his hands, (2) cleanse the meatus, (3) void a small amount into the toilet, and (4) void directly into the specimen container.
• Instruct the female patient to (1) thoroughly wash her hands; (2) cleanse the labia from front to back; (3) while keeping the labia separated, void a small amount into the toilet; and (4) without interrupting the urine stream, void directly into the specimen container.
• Follow the chain-of-custody protocol, if required. Monitor specimen collection, labeling, and packaging to prevent tampering. This protocol may vary by institution.
• Promptly transport the specimen to the laboratory for processing and analysis.

Post-Test

• Inform the patient that a report of the results will be made available to the requesting HCP, who will discuss the results with the patient.
• Ensure that results are communicated to the proper individual, as indicated in the chain-of-custody protocol.
• Recognize anxiety related to test results. Discuss the implications of abnormal test results on the patient’s lifestyle. Provide teaching and information regarding the clinical implications of the test results, as appropriate. Educate the patient regarding access to counseling services. Provide support and information regarding detoxification programs, as appropriate. Provide contact information, if desired, for the National Institute on Drug Abuse (www.nida.nih.gov).
• Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP. Answer any questions or address any concerns voiced by the patient or family.
• Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.

Related Monographs

• Refer to the Therapeutic/Toxicology table at the end of the book for related tests.